-Rotational storage devices are NOT recommended for indexing of
-large mail archives; but are fine for backup and usable for
-small instances.
+Rotational storage devices perform significantly worse than
+solid state storage for indexing of large mail archives; but are
+fine for backup and usable for small instances.
+
+As of public-inbox 1.6.0, the C<publicInbox.indexSequentialShard>
+option of L<public-inbox-index(1)> may be used with a high shard
+count to ensure individual shards fit into page cache when the entire
+Xapian DB cannot.
+
+Our use of the L</OVERVIEW DB> requires Xapian document IDs to
+remain stable. Using L<public-inbox-compact(1)> and
+L<public-inbox-xcpdb(1)> wrappers are recommended over tools
+provided by Xapian.